I don't do them often but I have enjoyed them. I can usually get through a few before "losing" but there are times where I fail miserably. My fantasy is to have a lady help out and do the stroking for me to make sure I'm not cheating.

Videos with changing porn scenes and onscreen instructions for how to masturbate. The first ones I saw had you stroke to various beats and rhythms, some faster some slower. I've seen some lately that just say 'Fast', "Slow', 'Edge', etc. The goal is to make it to the end of the video before you cum. I did see one recently where the goal was to cum five times. I think the video was an hour and a half.